360 Degree rotatable lifter arm for log singulator

ABSTRACT

The present invention  10  discloses a device for singulating individual logs from groups of logs for linear or transverse processing. The present invention discloses a log singulator having a fully rotatable lifter arm member, i.e., 360 degrees rotatable, which is used to singulate logs from groups of logs. The rotatable axle of the lifter arm may be located above the upstream “V” of the log cradle member. Furthermore, the lifter arm of the present invention will positively push the logs over the top point of the log cradle because it is rounded at the top point, thereby allowing the tip of lifter arm to remain in contact with the log. Lifter arms with 1 to 4 lifter arm tips are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.11/079,602, filed Mar. 14, 2005, now U.S. Pat. No. 6,978,879, which is acontinuation of U.S. application Ser. No. 10/883,625, filed Jul. 1,2004, now U.S. Pat. No. 7,021,451, which is a continuation of U.S.application Ser. No. 09/904,397, filed Jul. 12, 2001, now U.S. Pat. No.6,779,648, which claims the benefit of Provisional Application Ser. No.60/217,845, filed Jul. 13, 2000, each of which is hereby incorporatedherein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to log singulators, and moreparticularly, is concerned with a log singulator having a 360-degreerotatable lifting arm.

2. Description of the Prior Art

Log singulators have been described in the prior art. However, none ofthe prior art devices disclose the unique features of the presentinvention.

In U.S. Pat. No. 5,423,471, dated Jun. 13, 1995, Redekop disclosed a logsingulator for sorting, feeding and indexing in a downstream direction astack of logs into a stream of logs which has a first notched step and afirst set of collectively actuable lift arms pivotable about a firstaxis, and a second set of collectively actuable lift arms downstream ofthe first set of lift arms, actuable independently of the first set ofcollectively actuable lift arms and pivotable about a second axis, thefirst set of lift arms actuable from a lowered position to a raisedposition whereby the first set of lift arms are engageable with a log ata first engagement point thereby to raise the log from the stack oflogs, the first axis downstream of the first engagement point relativeto the direction of movement of said logs in said stream of logs, thefirst axis generally below the first notched step, the first notchedstep adapted to receive and hold the stack of logs, the first set oflift arms in the raised position positioning the log so as to depositthe log into a second notched step below the first set of lift arms inthe raised position and downstream of the first notched step, the secondset of lift arms actuable from a lowered position to a raised positionwhereby the second set of lift arms are engageable with the log in thesecond notched step at a second engagement point thereby to raise thelog from the second notched step, the second axis downstream of thesecond engagement point and generally below the second notched step, thesecond set of lift arms in the raised position positioning the log so asto deposit the log from the log singulator.

In U.S. Pat. No. 5,174,351, dated Dec. 29, 1992, Lindenblatt, et al.,disclosed an ending apparatus for positioning elongate objectscomprising, in combination, object singulating equipment for separatinga plurality of elongate objects in an inlet area into single objectswhile moving the objects in a first direction to an outlet area, andobject support rollers intermediate the inlet and outlet area forsupporting a separated, single elongate object. The object supportrollers are adapted to move the elongate object in a second directiontoward a reference surface independently of the object's movement in thefirst direction on the singulating device. The reference surface stopsmovement of the elongate object to establish a predetermined positionfor the elongate object. Establishing the position of the object permitsmore efficient handling during further processing.

In U.S. Pat. No. 4,585,114, dated Apr. 29, 1986, Liliano disclosed anapparatus for the transfer of mandrels from a lube conveyer to aparallel mandrel pre-insertion line which comprises a plurality oftransfer devices each of which has an arm for the direct transfer of themandrels which is disappearingly movable transversely between the saidconveyor and the said line, and a further pair of arms, one fixed andone movable, having upper saw-tooth profiles cooperating to effect astepwise displacement of the mandrels between the conveyor and the saidline.

While these log singulators may be suitable for the purposes for whichthey were designed, they would not be as suitable for the purposes ofthe present invention, as hereinafter described.

SUMMARY OF THE INVENTION

The present invention discloses a device for singulating individual logsfrom groups of logs for linear or transverse processing. The presentinvention discloses a log singulator having a fully rotatable lifter armmember, i.e., 360 degrees rotatable, which is used to singulate logsfrom groups of logs. The rotatable axle of the lifter arm may be locatedabove the upstream “V” of the log cradle member. Furthermore, the lifterarm of the present invention will positively push the logs over the toppoint of the log cradle because it is rounded at the top point, therebyallowing the tip of lifter arm to remain in contact with the log. Lifterarms with 1 to 4 lifter arm tips are disclosed.

In log utilization facilities, the need exists to singulate individuallogs from groups of logs for linear or transverse processing. Severaltypes of devices have been developed to accomplish this task. Thedevices currently available utilize a method of lifting logs over fixedgenerally V-shaped log cradles via a reciprocating motion generated bymechanical components. This particular motion has several disadvantages:the return motion of the lifting mechanism utilizes time in which theforward flow of logs being singulated is stopped; the reciprocatingmotion requires a bulky, complicated mechanism to perform the forwardand backward motion; as logs are lifted over the top of the V-shaped logcradle, movement of the log to complete the motion to the bottom of theupstream V-shaped pocket is dependent on gravity; logs with knots orthat are crooked may not slide into proper position; the reciprocatinglifting device is of an eccentric design, meaning that its weight is notbalanced, and, this off center weight disadvantage utilizesapproximately 25% of the total power to move a log from stage to stage;the V-shaped log cradles surfaces may be covered with smooth steelplating, and, the plating makes crooked or knotty logs “stand off” fromthe bottom of the V log cradle, and, if the logs are too far away fromthe lift position of the pocket, they will not be transferred from stageto stage.

Objects and advantages of the present invention are to disclose asingulation device which does not reciprocate, but makes a full360-degree motion. The rotary motion device of the present invention hasseveral advantages. Since the rotary singulation motion is continuous,in a constant direction, there is no lost time waiting or the liftingdevice to return to start position and, therefore, productivity of therotary device is greatly improved over the reciprocating device. Thedrive unit for the rotary motion is directly connected to the liftmechanism, eliminating the need for a complicated mechanical means,e.g., a transmission, to develop the reciprocating motion. Because themotion is continuous, the shape of the rotating lift arm is designed sothat the log is positively guided into the bottom of the upstreamV-shaped log cradle which eliminates the possibility of knots or crookedlogs hanging on the pocket surfaces. The rotary lifting device is of aconcentric design, meaning that its weight is substantially totallybalanced. Due to it being balanced, a power savings of up to 25% perstage can be realized to lift the same size log as a reciprocatingdesign. In the rotary design, an open skid concept is utilized, meaningthat the V-shaped log cradles are not covered with steel plating.However, alternatively, the skids may be plated over. The open designallows crooked or knotty logs to lay in the open V-shaped log cradle,conforming to the shape of the log. This permits the log to be liftedinto the proper position so that logs can be more efficientlytransferred from stage to stage of the log singulator.

The foregoing and other objects and advantages will appear from thedescription to follow. In the description reference is made to theaccompanying drawings, which form a part hereof, and in which is shownby way of illustration specific embodiments in which the invention maybe practiced. These embodiments will be described in sufficient detailto enable those skilled in the art to practice the invention, and it isto be understood that other embodiments may be utilized and thatstructural changes may be made without departing from the scope of theinvention. In the accompanying drawings, like reference charactersdesignate the same or similar parts throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more fully understood, it will now bedescribed, by way of example, with reference to the accompanyingdrawings in which:

FIG. 1 is a perspective view of the present invention.

FIG. 2 is a side elevation view of parts of the present invention.

FIG. 3 is a side elevation view of parts of the present invention.

FIG. 4 is a side elevation view of parts of the present invention.

FIG. 5 is a side elevation view of parts of the present invention.

FIG. 6 is a side elevation view of parts of the present invention.

FIG. 7 is a side elevation view of parts of the present invention.

LIST OF REFERENCE NUMERALS

With regard to reference numerals used, the following numbering is usedthroughout the drawings.

10 log singulator

12 lifter arm

14 axle

16 center line of axle

18 “V” bottom

22 log

24 top point

26 tip of lifter arm

28 sidewall

30 support members

32 front cross member

34 rear cross member

36 log cradle

38 log cradle

40 log cradle

42 log cradle

44 lifter arm

46 lifter arm

48 lifter arm

50 lifter arm face

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now descriptively to the drawings, in which similar referencecharacters denote similar elements throughout the several views, FIGS. 1through 7 illustrate the present invention wherein a 360 degreerotatable lifter arm for use on a log singulator is disclosed.

Turning to FIG. 1, therein is shown a perspective view of a logsingulator 10 having multiple lifter arms 12 installed thereon. Multipleaxles are provided 14 upon which the lifter arms 12 rotate which axleextends through and serves multiple lifter arms 12. The log singulatorcomprises a pair of sidewalls 28 and a plurality of vertically standingsupport members 30 held upright by a cross member 32 on the first,front, lower end of the log singulator 10 and a second, back, crossmember 34 on the rear or upper end of the log singular 10. Axles 14 arejournalled through sidewalls 28 and support members 30 and equipped withbearing means as would be done by one skilled in the art. Furthermore,means for rotating the multiple axles 14 in a counterclockwise and/orclockwise direction would also be provided. It should be seen that thelog singulator 10 operates by moving logs in a step-wise fashion up thelog singulator by first moving a log from log cradle 36 to the nexthigher log cradle 38 and then up to the next higher log cradle 40 andthen up onto the highest log singulator station, i.e., the log cradle 42where the log would then be moved by other machinery for furtherproceeding. The first set of lifter arms 44 move the log from log cradle36 downstream to log cradle 38 where a second set of lifter arms 46contact the logs to move them downstream to log cradle 40 where a thirdset of lifter arms 48 move the logs downstream to log cradle station 42.

Turning to FIG. 2, therein is shown a side view of the present invention10 showing a left sidewall 28 along with a first lifter arm 44, a secondlifter arm 46, and a third lifter arm 48, all shown in relationship tologs 22. It can be seen here that the lifter arms 12 rotate 360 degrees.It should also be noted that as shown with lifter arm 46 that the tip ofthe lifter arm 26 is slightly longer than the top point 24 of the logcradle so that the lifter arm 46 will positively push the log 22 overthe top point 24 of the log cradle because the log cradle is rounded atthe top point 24, thereby allowing the tip 26 of arm 46 to remain incontact with logs 22 in order to positively push the logs 22 to the nexthigher or downstream log cradle. Front cross member 32 is also shown.

Turning to FIG. 3, therein is shown a side elevation view of anotherlifter arm embodiment of the present invention 10. Shown therein is thelifter arms 12 having a different design wherein the lifter arm tips 26overlap each other requiring that the lifter arms be disposed off-centerfrom each other in order to move logs downstream or up the logsingulator in order to allow tips 26 to clear each other.

Turning to FIG. 4, therein is shown a side elevation view of anotherlifter arm embodiment of the invention shown in FIG. 3 wherein thelifter arms 12 are shown spaced apart so that the tips 26 thereof do notoverlap; therefore, allowing the tips 26 of the lifter arms 12 to cleareach other without being disposed off-center from each other.

Turning to FIG. 5, therein is shown a side elevation view of anotherlifter arm embodiment of the present invention wherein the lifter arms12 have only one tip 26 having only one face with which to contact logs52.

Turning to FIG. 6, therein is shown a side elevation view of anotherlifter arm embodiment of the present invention wherein the lifter arms12 have three tips 26 having three faces 50 with which to contact logs22.

Turning to FIG. 7, therein is shown a side elevation view of anotherlifter arm embodiment of the present invention wherein the lifter arms12 have four tips 26 having four faces 50 with which to contact logs 22.

Many specific details contained in the above description merelyillustrate some preferred embodiments and should not be construed as alimitation on the scope of the invention. Many other variations arepossible.

1. A method for conveying and singulating logs, the method comprising:receiving logs along a conveying path defined by stationary log-bearingsurfaces of a log singulator; and rotating a shaft of the log singulatorat least 360 degrees and thereby rotating a plurality of lift armsextending from the shaft such that the lift arms of the shaft engage oneof the logs on a lower location of the log-bearing surfaces and lift thelog over a top point to a higher location on the log-bearing surfaces,such that the log is lifted over the top point and conveyed along theconveying path toward the rear end of the frame, wherein the top pointis defined by one or more surfaces that define a generally smoothcontour over which the logs can be moved.
 2. A method according to claim1, wherein said rotating step comprises rotating the shaft continuouslyin a single direction.
 3. A method according to claim 1, wherein saidrotating step comprises conveying the log horizontally and upward.
 4. Amethod according to claim 1, further comprising supporting the shaft ina configuration substantially parallel to the log-bearing surfaces.
 5. Amethod according to claim 1, further comprising rotatably supporting theshaft through apertures in support plates defining the log-bearingsurfaces.
 6. A method according to claim 1, wherein said rotating stepcomprises rotating the shaft with a drive system directly connected tothe shaft.
 7. A method according to claim 1, wherein said rotating stepcomprises engaging the lift arms with a log in an upstream log cradledefined by the log-bearing surfaces of the singulator and lifting thelog along the log-bearing surfaces so that a tip of each lift armextends above a crest between the upstream log cradle and a downstreamcradle, such that the lift arms positively push the log over the crestinto the downstream log cradle.
 8. A method according to claim 7,wherein said rotating step comprises dipping the tips of the lift armsbelow the log-bearing surfaces at a point between the crest and thedownstream log cradle and thereby releasing the log from the lift armsso that the logs are free to move down one of the log-bearing surfacesdefining an upstream side of the downstream cradle and be stopped by oneof the log-bearing surfaces defining a downstream side of the downstreamcradle without engaging the lifter arms of a downstream shaft.
 9. Amethod according to claim 1, further comprising providing the lift arms,each lift arm defining front and back surfaces that are generallyparallel.
 10. A method according to claim 1, further comprisingproviding the lift arms, each lift arm defining a plurality ofcircumferentially spaced tips.
 11. A method for conveying andsingulating logs, the method comprising: receiving logs along aconveying path defined by stationary log-bearing surfaces of a logsingulator; and rotating a shaft of the log singulator at least 360degrees and thereby rotating a plurality of lift arms extending from theshaft such that the lift arms of the shaft engage one of the logs in anupstream log cradle defined by the log-bearing surfaces of thesingulator and lift the log along the log-bearing surfaces, a tip ofeach lift arm extending above a crest between the upstream log cradleand a downstream cradle such that the lift arms lift the log andpositively push the log over the crest into the downstream log-cradle,the tips of the lift arms dipping below the log-bearing surfaces at apoint between the crest and the downstream log-cradle such that the logis released from the lift arms and free to move down one of thelog-bearing surfaces defining an upstream side of the downstream cradleand be stopped by one of the log-bearing surfaces defining a downstreamside of the downstream cradle without engaging a downstream shaft.
 12. Amethod according to claim 11, wherein said rotating step comprisesrotating the shaft continuously in a single direction.
 13. A methodaccording to claim 11, wherein said rotating step comprises conveyingthe log horizontally and upward.
 14. A method according to claim 11,further comprising supporting the shaft in a configuration substantiallyparallel to the log-bearing surfaces.
 15. A method according to claim11, further comprising rotatably supporting the shaft through aperturesin support plates defining the log-bearing surfaces.
 16. A methodaccording to claim 11, wherein said rotating step comprises rotating theshaft with a drive system directly connected to the shaft.
 17. A methodaccording to claim 11, further comprising providing the lift arms, eachlift arm defining front and back surfaces that are generally parallel.18. A method according to claim 11, further comprising providing thelift arms, each lift arm defining a plurality of circumferentiallyspaced tips.